clipka wrote:

 > as it requires an infinitely long memory tape

No it doesn't. It only requires an unbounded memory tape. There's a huge 
difference.

> Therefore, a machine programmable only by re-wiring /cannot/, by 
> definition, be Turing-complete.

I don't think that's right. Wire up the computer to be a UTM, and it's 
Turing complete.

Unless you are unable to wire up Colossus in such a way that it can 
interpret arbitrary Turing machine programs, it it Turing complete. I.e., 
Colossus would be the "simulating" Universal Turing Machine on which you 
could interpret any other Turing machine.

 > Now stating that a machine is "Turing-complete" is equivalent to saying 
that it is capable of simulating not just /some/ Turing machine, but a 
/Universal/ Turing machine

Any real machine capable of simulating an arbitrary Turing machine is Turing 
complete. The only limitation would be whether Colossus had enough wires to 
do the job, really. But you could conceive of a machine with hard wires that 
simulates a Turing machine.

Indeed, you're using one.

-- 
   Darren New, San Diego CA, USA (PST)
   I ordered stamps from Zazzle that read "Place Stamp Here".

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